Plastic closures molded from polymeric material, such as polypropylene and polyethylene, find widespread application for use in association with containers having beverages and food products. For some applications, such as for containers for food products for which ready access is desirable, relatively large-diameter closures, which may have diameters on the order of 63 to 110 millimeters, are desirably employed.
Typically, closures of this nature do not include an integral tamper-indicating pilfer band or the like, but instead typically include an internally-threaded annular skirt portion which terminates in a free edge. In the past, the portion of the skirt below the thread formation, which enhances the visual appeal of the closure and facilitates gripping by consumers, has been made heavier, and thus more costly, than is typically required for the closure to function as desired. However, this lower skirt portion is preferably configured to exhibit sufficient strength to facilitate “stripping” of the closure from an associated internal core pin, that is, effecting removal of the closure from the core pin without resort to a collapsible core, or a relative unthreading motion of the closure.
The present invention provides a molded plastic closure exhibiting enhanced column strength, which facilitates efficient formation by permitting stripping from an associated core pin during molding, without resort to a relatively complex collapsible core. At the same time, the closure desirably requires the use of less plastic material while still exhibiting the desired strength, thus further facilitating cost-effective formation and use.